Compost bins are currently in extensive use as they provide an economic means for transforming what has been generally regarded as waste into a useful material. Unassisted, however, the chemical process of decomposition is relatively slow and the advantages of controlling the process inexpensively such that maximum efficiency in the production of compost is achieved is highly desirable. A compost bin which goes some way towards achieving more efficient decomposition is disclosed in U.K. patent specification No. 1,427,331.